This invention relates to a track system for vehicles, and in particular, to an improved drive wheel for driving the track system.
Agricultural implements such as tractors, combines and the like are commonly used in agricultural fields for a variety of jobs. Typically, these agricultural implements incorporate tires on which the implement is supported. Since these types of large agricultural implements are quite heavy, the weight of agricultural implements are distributed to a relatively small area on the tires of the implements. As a result, the tires on the agricultural implements tend to compact the soil in the fields. Compacted soil discourages the growth of crops planted in the fields which need loose soil to flourish.
In addition, since agricultural fields are often wet due to rain or watering, agricultural implements which enter the fields become bogged down in the mud due to the fact that there is such a small area of the tire in contact with the soil. As such, it is highly desirable to develop a track system for vehicles which disburses the weight of the agricultural implement over a larger area so as to reduce the compaction of the soil in the agricultural fields and to provide a track with a larger surface area which contacts the soil so as to prevent the agricultural implement from becoming bogged down in mud in the fields.
A prior track system for vehicles is disclosed in Kelderman, U.S. Pat. No. 5,452,949, assigned to the Assignee of the present invention and incorporated herein by reference. The Kelderman '949 patent discloses a track suspension system for a vehicle having a frame and a continuous track. The drive wheel is attached to the frame for engaging and driving the continuous flexible track. The drive wheel has a plurality of drive projections disposed thereon which engage depressions in the rubber track. As the drive wheel rotates, it engages and drives the continuous flexible track. Since the drive projections of the drive wheel are rigid, repeated engagement of the projections with the depressions in the rubber track has a tendency to cause cracking of the continuous flexible track. Consequently, it would be highly desirable to provide a drive wheel having drive projections which do not damage the flexible track after extended use.
Therefore, it is a primary object and feature of the present invention to provide a drive wheel for engaging and driving a continuous flexible track of a track system for a vehicle.
It is a further object and feature of the present invention to provide a drive wheel of a track system for engaging and driving a continuous flexible track which does not damage the track during extended use.
It is a still further object and feature of the present invention to provide a drive wheel of a track system for engaging and driving a continuous flexible track which is inexpensive to manufacture and simple to assemble.
In accordance with the present invention, a drive wheel is provided. The drive wheel is mounted on a rotatable axle vehicle for driving a continuous flexible track. The drive wheel includes a central hub mountable on the axle rotational movement therewith. A first rim wall extends radially from the central hub. A second rim wall also extends radially from the central hub and is spaced from the first rim wall so as to define a circumferentially extending void in the drive wheel therebetween. A plurality of circumferentially spaced rollers are rotatably supported within the void for engaging a portion of the track.
Each rim wall includes a generally planar portion which is parallel to the other. Each of the rollers includes first and second opposite ends. Each end of each roller is rotatably supported by a corresponding rim wall. Each of the rollers is rotatable about and extends along a corresponding axis. The axis of each roller is generally parallel to the axle of the vehicle.
Each of the rollers include a track engaging surface for engaging the portion of the track. The track engaging surface is generally cylindrical. First and second enlarged heads may be positioned on opposite ends of the track engaging surface of each roller. The first enlarged head of each roller is rotatably mounted to the first rim wall and the second enlarged head of each roller is rotatably mounted to the second rim wall.
Each roller further includes a first guide surface extending between the track engaging surface in the outer surface of the first enlarged head and the second guide surface extending between the track engaging surface in the outer surface of the second enlarged head.
The first and second guide surfaces of each roller diverge from each other at a predetermined angle.
It is contemplated that each roller be fully received within a circumferentially extending void in the drive wheel. The drive wheel may include a plurality of circumferentially spaced depressions in each rim wall. A bearing sleeve may extend through each roller. The bearing sleeve of each roller having a first and seated in a corresponding depression in the first rim wall, and a second opposite end seated in a corresponding depression in the second rim wall.
In accordance with a still further aspect of the present invention, a drive wheel is provided. A drive wheel is mountable on a rotatable axle of the vehicle for driving a continuous flexible track. The track includes an inner surface having a lug projecting therefrom. The drive wheel includes a central mounting portion mountable on the axle for rotational movement therewith. First and second guide walls project radially from the second mounting portion and define a circumferentially extending void therebetween. Each guide wall includes a radially outer edge which engages the flexible track. First and second parallel rollers are rotatably supported within the void and define a lug receiving gap therebetween. The guide walls engage the inner surface of the track and guide the lug into the lug receiving gap between the rollers upon rotation of the axle.
It is contemplated that the first and second guide walls be generally parallel to each other. Each of the rollers is rotatable about and extends along a corresponding roller axis. Each roller axis is generally perpendicular to the guide walls.
Each roller includes a lug engaging surface. The lug engaging surface of each roller engaging the lug when the lug is received within the lug receiving gap. The lug engaging surface of each roller is generally cylindrical and may include first and second enlarged heads at opposite ends thereof. First and second guide surfaces extend from the outer surface of a corresponding enlarged and converged toward the lug engaging surface of the roller. Each roller may include a hollow, bearing sleeve having first and second opposite ends and defining a generally cylindrical outer surface. A hollow, lug engaging sleeve is positioned about the bearing sleeve between the first and second ends thereof such that the inner surface of the lug engaging sleeve forms a rotational interface with the outer surface of the bearing sleeve. Each guide wall of the drive wheel may include a plurality of circumferentially spaced depressions therein. The first end of each bearing sleeve is supported within a corresponding depression in the first guide wall and the second end of bearing sleeve is received within the corresponding depression in the second guide wall.
In accordance with yet a further aspect of the present invention, a track apparatus having a frame is provided for mounting to a rotatable axle of a vehicle. The track apparatus includes a continuous flexible track having an upper length and ground engaging lower length. The flexible track includes an inner surface having a plurality of lugs projecting therefrom. A drive wheel engages the inner surface of a flexible track along the upper length. The drive wheel is mountable to the rotatable axis for rotational movement therewith. A circumferentially extending void is provided in the drive wheel. A plurality of parallel, spaced rollers are rotatably mounted within the void in the drive wheel. Each of the rollers sequentially engage a corresponding lug in response to rotation of the drive wheel on the axle.
The track apparatus may also include a leading idler assembly attached to the frame and having a leading idler arm and leading idler wheel. The leading idler wheel engages the track and is rotatably mounted to the distal end of the leading idler arm. A trailing idler assembly is attached to the frame and has a trailing idler arm and a trailing idler wheel. The trailing idler wheel engages the track and is rotatably mounted to the distal end of the trailing idler arm. A mid-roller or bogie assembly engages the lower length of the track and is attached to one of the idler arms.
The drive wheel of the track apparatus includes an axial center and first and second guide walls extending radially therefrom. The guide walls of the drive wheel define a void therebetween. Each guide wall terminates at a radially outer edge having a predetermined radius. The outer edge of each guide wall engages the inner surface of the flexible track in order to guide each lug of the flexible track into engagement with the rollers of the drive wheel.